The simplified value of 1.2 + (1.2)2 + (1.2)3 is

To simplify a sum of successive powers of the same decimal base, evaluate each power separately by direct multiplication, then add the results — no special identity is needed when the exponents are small and consecutive.

1. Identify the three terms to evaluate: 1.21, 1.22, and 1.23.

2. Compute 1.22 = 1.2 × 1.2 = 1.44.

3. Compute 1.23 = 1.44 × 1.2 = 1.728.

4. Add all three terms: 1.2 + 1.44 + 1.728 = 4.368.

As a check, re-add the terms in reverse order — 1.728 + 1.44 + 1.2 — which gives the same total, 4.368, confirming the sum is correct.

So the simplified value of the expression is 4.368.